Carbonizing compound and process of making and using it



Jill 21 1925. 1,546,937

S. B. MATHEWSON ET AL CARBONIZING COMPOUND AND PROCESS OF MAKING AND USING IT Original Filed April 5. 1922 ATTOZNEYJ Patented July 21, 19250 UNlThm UFFICE.

$TANLEY 13. IMATHEHSON, SPRING-FIELD. JVALTEB Fl. JAMISON, 0F DAYTON, OHIO, ASSIGNORS 'IO "W'ALTFER K. JAJRHSON, fiTI-LNLEY l3. JBEATHE'W'SQN, HOWARD F. MARSTON, (ll/IRS.) "W. JAIREISUN, (TiltIRfi-l.) S. B. NIATHEW'EON, TRUSTEES OF THE LECAR CARBON COhiI-EAITY, OF SPRINGFEELD, 0351110, A TRUST ESTATE.

CARBONIZING COMPOUND AND PROCESS OF TEAKING AND USING IT.

Original applications filed April 3, 1922, Serial No. 5423,2745 and August 7, 1922, Serial No. 580,225. Divided and this application filed. December 6, 1923. Serial No. 678,986.

To aZZ whom it may concern:

Be it known that we, STANLEY l3. MATH- nwson and l VALTER K. JAMIsoN, citizens of the United States, residing at Springfield, Clark County, Chio, and Dayton, Montgomery County, Ohio, respectively, have invented certain new and useful Improvements in Carbonizing Compounds and Processes of Making and Using Them, of which the following is a specification, reference being had therein to the accompanying drawing.

Our invention relates to a carbonizing compound and the process of making); it and using it for carbonizing metal, and in particular case hardening steel. The object of our invention is to utilize scrap leather by the treatment of our invention hereinafter described and claimed.

An additional object of our invention is to provide a new product by this treatment which may be utilized as a carbonizing material.

Itis a further object of our invention to provide a method of utilizing our new procluct .in case hardening metals such as steel in order to provide a very deep case in the minimum of time and economically.

This is a division of applications No. 549,274, filed Apr. 3, 1922, and 580,225, filed Aug. 7, 1922. I

Referring to. the drawings Fig. 1 is a carbonizing can; I

Fig. 2 is a diagrammatic view of the furnace in which the carbonizing can is placed with the scrap leather in order to reduce it to the form of the product now in question;

Fig. 3 is a diagrammatic view of the rolls andscreen for determining the size and grade of the resulting carbonized procluct;

Fig. t is an end elevation of a piece of steel before treatment with this carbonizing material;

Fig. 5 is a similar view after carbonization showing the case;

Fig. 6 is a section of a carbonizing box packed with the carbonizing material involved herein showing the articles being carbonized and the arrangement of their packing.

lit will be understood that the foregoing drawings are diagrammatic merely and are only for the purpose of illustration.

Referring to the drawings in detail, 1 is a carbonizing can or metal container having a lid 2 with apertures 3 in the lid thereof. The scrap leather is placed in this can and the can is placed in an oven 4. This oven is heated by any desired means as for instance by burners such as at 5. It will be understood. that this illustration of the burners is typical only and that any kind of heating apparatus may be employed. The cans are sealed and the lids are tight fitting. The openings 3 are provided in the cans to permit of the adjustment of the internal pressure and to permit of the escape of gases within the container.

The cans are preferably packed in an oil furnace, the temperature of which has been brought up to 1200 degrees F, at which time the burners are shut off and the furnace sealed with the exception of the regular ventilation therefor. It is customary to allow the furnace to remain closed for about sixyhours, after which time the containers can be removed and the finished product may be removed from each one of the ind vidual containers. It is then criuhed be tween the rollers 66 and screened by the screen 7 which is preferably about of a mesh. The purpose of this is to reduce it to a suitable size for carbonizing purposes.

Process of hardening Stfi].

The finished product thus secured s us d as follows: The parts to be carbonized ro thoroughly cleansed in an alkali solution in order to remove all dirt and oil. Any cleansing solution of similar character may be employed. They are then packed in the boxes 8 so that the parts 9 will be arranged in layers in the carbonizing material 10. The top of the box is sealed with fire clay as at 11. It is the preferred practice to place a layer of the carbonizing material. then a layer of parts separated from one Ill another by the carbonizing material, a layer of carbonizing material and another layer of parts, and so on. The whole packing is covered with a layer of the carbonizing material.

If desired the lid may be of metal and sealed with fire clay. Any common practice of this sort may be f llowed. The boxes are then placed in a carbonizing furnace and the temperature brought up to J00 degrees F. and held at this temperature for about three hours, but this time and temperature varies upon the depth of case desired, the size of the parts to be carbonized and the size of the carbonizing boxes.

In the event the furnace boxes are placed therein greater time will be necess desired result.

The bores employed are usually about eight and one-half inches in dia zter, eleven inches deep and walls about 34; thick. it takes about three hours to bring a packed box up to the temperature of 1T00 degrees, the temperature used for carbonizing.

For instance, in the case of ca bonizing S. A. E. steel, it has been found good practice with this carboniziug material to hold the carbonizin g heat at 17 0 degrees F. for five hours when packed in a boa: of the above mentioned dimensions in order to obtain a 3 g depth of case.

The preferred method after this temperature has been maintained this desired length of time is to allow the case hardened steel parts to cool in the carboniziug boxes before they are exposed to the air.

We do not desire to confine our invention to any particular type of furnace for the heat treatment. An open type furnace may be employed in which the temperature has been brought up to 1450 degrees F. before the parts are placed in the furnace. It will then customarily require about fifteen to twenty minutes to bring a 3 part, speaking in terms of diameters, up to 1450 degrees. The parts are then removed and quenched in brine or oil. It will be understood that these parts are always removed from the furnace and quenched on the rising heat.

In the second method a salt bath may be used and the parts are immersed in this solution. After the solution has been brought up to 1450 degrees F. the parts are removed and quenched in brine or oil. [this type of furnace is usually designated a cyanioe furnace. It will be understood that the ire doesnot come in direct contact with the work as acast iron tank is placed in the furnace and the salt solution is placed in the tankand melted by the heat coming in contact with the outside of the tank.

It will be further understood that it is preferred by us that all quenching solutions is cold when the .Joportmnately y to effect the be retained as at low a temperature as possible, which is accomplished by any well known means such as circulating' the solution through cooling coils.

Referring to Figs. 4 and 5, 12 is a specimn of steel and is the case.

When the carbonizing material so produced by the above mentioned process is examined vit-h the naked eye it appca :s to be a porous cellular structure with a highly vitrified appearance. The apertures there in and therethrough are irregular in shape and size.

The carbonaceous material referred to herein as the carbonizing compound. is generally composed of approximately to 31% volatile matter, about 3% moisture, about 58% fixed carbon and about 8% ash.

it will be understood that these amounts are approximate.

Upon analysis the ash will usually develop a ferric or-cid color. The volatile matter consists of various gases. In these gases a varying amount of ammonia will be found and the usual reaction to litmus will be alkaline.

li hile we have shown and described cer tain features as constituting our invention, it will be understood that parts have been shown for purposes of illustration only, and that we do not desire to be limited to such details, as obvious modifications will occur to persons skilled in the art.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent, is z 1. In a method of producing a carbonizing material, placing scrap leather and the like in a receptacle closed except for small holes in it, placing a receptacle in a furnace and heating the receptacle therein, allowing the receptacle and its contents to cool, sealing the furnace except for natural draft and allowing the furnace to cool with the boxes therein for a predetermined period.

2. In a method of producing a carbonizing material, placing scrap leather and the like in a partially sealed receptacle in a furnace and heating the receptacle therein, allowing the receptacle and its contents to cool, sealing the furnace except for natural draft and allowing the furnace to cool with the boxes therein for a predetermined period, removing the boxes, crushing the material and screening it.

3. In a process of producing a carbonizing material, placing scrap leather and the like in partially sealed containers having apertures in the top thereof for the exit of gases therefrom, placing the containers in a furnace, heating the containers for a predetermined period, allowing the receptacle and its contents to cool but allowing the container to remain within the furnace a predetermined period and removing the containers and the material therefrom.

4. In a process of produclng a carbon material, placing scrap leather in a receptacle which is sealed save for a vent, heating until the temperature is brought up to 1200 degrees Fahrenheit, sealing the furnace and allowing it to remain closed for about six hours, and opening the furnace and removing the material from the container.

5. In a process of producing a carbon material, placing scrap leather in a partially sealed container, heating it until it reaches a temperature of about 1200 degrees Fahrenheit, sealing the furnace in which the container is located and allowing the container and its contents to cool, allowing a portion of the gases generated to escape during the heating period and allowing the remainder of the gases generated to be reabsorbed by the material upon cooling, where by the material upon completion will have the appearance of a granular mass or of a vitrified sponge, consisting of about 60 per cent carbon, 30 to 40 per cent Volatile matter in suspension, and the remainder in moisture and ash.

6. In a process of producing a carbon material, treating scrap leather by heating it to a predetermined temperature, generating gases from it during the heating period partially confining the generated gases and allowing the mass to cool to reabsorb said gases while cooling, whereby a resulting compound is produced, consisting of carbon and nitrogen products in suspension therein adapted to be released upon the heating of the product to a predetermined temperature,

7. In a process of producing a carbon material, treating scrap leather by heating it to a predetermined temperature, generating gases from it during the heating period partially confining the generated gases and allowing it to cool to reabsorb said gases while cooling, whereby a resulting compound is produced, consisting of carbon and nitrogen products in suspension therein adapted to be released upon the heating of the product to a predetermined temperature, said carbon consisting of about 60 per cent of the product and the nitrogenous products consisting of about 30 to 40 per cent of the product.

In testimony whereof we affix our signatures.-

STANLEY B. MATHEWSON. WALTER K. JAMISON. 

